Melt 1/4 cup margarine and 4 cups marshmallows. Add 4 cups Rice Krispies. Pat in buttered 9 x 13 inch pan. Melt caramels, 1/4 cup margarine and sweetened condensed milk together. Pour over Rice Krispies in pan. Refrigerate 30 to 40 minutes. Prepare another Rice Krispie mixture like the first. Put on top of caramel layer. Keep refrigerated.
